Adding a printer to your Lubuntu computer/system/network is fairly straight-forward. First; make sure the printer itself is plugged-in, connected to the computer and/or network, has paper and is powered-on.
UNDER THE HOOD
CUPS, Foomatic and more: CUPS manages print jobs and print queues with the Internet Printing Protocol (IPP) and a basic set of PostScript Printer Description (PPD) files. CUPS also features auto-detection of most any network printer. Foomatic is a filter that rides on top of CUPS; providing it the newest PPD files to describe printer capabilities. Foomatic parts are also included in applications like GIMP and LibreOffice. CUPS and Foomatic work together to cover almost any printer you could add.
Earlier versions of the C4C Lubuntu 16.04 ReSpin did not include CUPS
To install, go to Menu --> System Tools --> LXTerminal or [Ctrl]+[Alt]+[T]
and type (or copy and paste):
sudo apt update && sudo apt install cups
Some HP Printers do better with their own HPLIP system installed (download it here). Other Printer manfufacturers like Brother, Canon, Lexmark, Samsung, Xerox have non-free drivers and plug-ins they would prefer you use too. See the Ubuntu Community Documentation about them here.
Check the Hardware Support Components - Printers page at the Ubuntu Wiki. See if your printer is listed in the OpenPrinting DataBase from LinuxFoundation. See the Foomatic Man Page and see the latest posts # tagged with Printer on the Ubuntu Community Forums